/*----------------------------------------------------------------------------

DIGCLOCK.C --         Digital Clock

(c) Charles Petzold, 1998

----------------------------------------------------------------------------*/

#include <windows.h>

#define ID_TIMER    1

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
	static TCHAR szAppName[] = TEXT ("DigClock") ;
	HWND                                 hwnd ;
	MSG                                  msg ;
	WNDCLASS                      wndclass ;
	wndclass.style                                       = CS_HREDRAW | CS_VREDRAW ;
	wndclass.lpfnWndProc                                 = WndProc ;
	wndclass.cbClsExtra                                  = 0 ;
	wndclass.cbWndExtra                                  = 0 ;
	wndclass.hInstance                                   = hInstance ;
	wndclass.hIcon                                      = LoadIcon (NULL, IDI_APPLICATION) ;
	wndclass.hCursor                                     = LoadCursor (NULL, IDC_ARROW) ;
	wndclass.hbrBackground                       = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
	wndclass.lpszMenuName                        = NULL ;
	wndclass.lpszClassName                       = szAppName ;

	if (!RegisterClass (&wndclass))
	{
		MessageBox (  NULL, TEXT ("Program requires Windows NT!"), szAppName, MB_ICONERROR) ;
		return 0 ;
	}

	hwnd = CreateWindow (szAppName, TEXT ("Digital Clock"),
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT, CW_USEDEFAULT,
		CW_USEDEFAULT, CW_USEDEFAULT,
		NULL, NULL, hInstance, NULL) ;

	ShowWindow (hwnd, iCmdShow) ;
	UpdateWindow (hwnd) ;

	while (GetMessage (&msg, NULL, 0, 0))
	{
		TranslateMessage (&msg) ;
		DispatchMessage (&msg) ;
	}

	return msg.wParam ;
}


void DisplayDigit (HDC hdc, int iNumber)
{
	static BOOL  fSevenSegment [10][7] = {
		1, 1,     1,     0,     1,     1,     1,            // 0
		0, 0,     1,     0,     0,     1,     0,            // 1
		1, 0,     1,     1,     1,     0,     1,            // 2
		1, 0,     1,     1,     0,     1,     1,            // 3
		0, 1,     1,     1,     0,     1,     0,            // 4
		1, 1,     0,     1,     0,     1,     1,            // 5
		1, 1,     0,     1,     1,     1,     1,            // 6
		1, 0,     1,     0,     0,     1,     0,           // 7
		1, 1,     1,     1,     1,     1,     1,            // 8
		1, 1,     1,     1,     0,     1,     1 } ;         // 9

		static POINT ptSegment [7][6] = {
			7,  6,  11,   2,  31,  2, 35,  6,  31, 10, 11, 10,
			6,  7,  10, 11, 10, 31, 6,   35, 2,  31, 2,  11,
			36, 7,  40, 11, 40, 31, 36,  35, 32, 31, 32, 11,
			7 , 36, 11, 32, 31, 32, 35,  36, 31, 40, 11, 40,
			6 , 37, 10, 41, 10, 61, 6,   65, 2,  61, 2,  41,
			36, 37, 40, 41, 40, 61, 36,  65, 32, 61, 32, 41,
			7 , 66, 11, 62, 31, 62, 35,  66, 31, 70, 11, 70 } ;

			int           iSeg ;
			for (iSeg = 0 ; iSeg < 7 ; iSeg++)
				if (fSevenSegment [iNumber][iSeg])
					Polygon (hdc, ptSegment [iSeg], 6) ;
}


void DisplayTwoDigits (HDC hdc, int iNumber, BOOL fSuppress)
{
	if (!fSuppress || (iNumber / 10 != 0))
		DisplayDigit (hdc, iNumber / 10) ;

	OffsetWindowOrgEx (hdc, -42, 0, NULL) ;
	DisplayDigit (hdc, iNumber % 10) ;
	OffsetWindowOrgEx (hdc, -42, 0, NULL) ;
}

void DisplayColon (HDC hdc)
{
	POINT ptColon [2][4] = {      2,     21,    6,     17,    10,    21,    6,    25,
		2,51,    6,     47,    10,    51,    6,     55 } ;

	Polygon (hdc, ptColon [0], 4) ;
	Polygon (hdc, ptColon [1], 4) ;

	OffsetWindowOrgEx (hdc, -12, 0, NULL) ;
}


void DisplayTime (HDC hdc, BOOL f24Hour, BOOL fSuppress)
{
	SYSTEMTIME st ;
	GetLocalTime (&st) ;
	if (f24Hour)
		DisplayTwoDigits (hdc, st.wHour, fSuppress) ;
	else
		DisplayTwoDigits (hdc, (st.wHour %= 12) ? st.wHour : 12, fSuppress) ;
	DisplayColon (hdc) ;
	DisplayTwoDigits (hdc, st.wMinute, FALSE) ;
	DisplayColon (hdc) ;
	DisplayTwoDigits (hdc, st.wSecond, FALSE) ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)
{
	static BOOL           f24Hour, fSuppress ;
	static HBRUSH         hBrushRed ;
	static int                    cxClient, cyClient ;
	HDC                                         hdc ;
	PAINTSTRUCT   ps ;
	TCHAR                                szBuffer [2] ;

	switch (message)
	{
	case   WM_CREATE:
		hBrushRed = CreateSolidBrush (RGB (0, 255, 255)) ;
		SetTimer (hwnd, ID_TIMER, 1000, NULL) ;// fall through

	case   WM_SETTINGCHANGE:
		GetLocaleInfo (LOCALE_USER_DEFAULT, LOCALE_ITIME, szBuffer, 2) ;
		f24Hour = (szBuffer[0] == '1') ;
		GetLocaleInfo (LOCALE_USER_DEFAULT, LOCALE_ITLZERO, szBuffer, 2) ;
		fSuppress = (szBuffer[0] == '0') ;
		InvalidateRect (hwnd, NULL, TRUE) ;
		return 0 ;

	case   WM_SIZE:
		cxClient = LOWORD (lParam) ;
		cyClient = HIWORD (lParam) ;
		return 0 ;

	case   WM_TIMER:
		InvalidateRect (hwnd, NULL, TRUE) ;
		return 0 ;

	case   WM_PAINT:
		hdc = BeginPaint (hwnd, &ps) ;
		SetMapMode (hdc, MM_ISOTROPIC) ;
		SetWindowExtEx (hdc, 276, 72, NULL) ;
		SetViewportExtEx (hdc, cxClient, cyClient, NULL) ;
		SetWindowOrgEx (hdc, 138, 36, NULL) ;
		SetViewportOrgEx (hdc, cxClient / 2, cyClient / 2, NULL) ;
		SelectObject (hdc, GetStockObject (NULL_PEN)) ;
		SelectObject (hdc, hBrushRed) ;
		DisplayTime (hdc, f24Hour, fSuppress) ;
		EndPaint (hwnd, &ps) ;
		return 0 ;

	case   WM_DESTROY:
		KillTimer (hwnd, ID_TIMER) ;
		DeleteObject (hBrushRed) ;
		PostQuitMessage (0) ;
		return 0 ;
	}
	return DefWindowProc (hwnd, message, wParam, lParam) ;
}
